Practice-based research networks (PBRNs) gave great potential to narrow the gap between the generation and the implementation of scientific evidence. However, PBRNs have been limited by the lack of infrastructure for gathering and using health system information. The Research Association of Practicing Physicians (RAPP) is a regional PBRN, consisting of 239 family physicians, and their affiliated clinicians and staff members in 116 practices in Northeast Ohio. RAPP has conducted an integrated series of research projects ranging from observational studies to clinical trials, including collaboration with other local and national networks This research has produced more than 30 scientific publications that are fostering a higher level of basic understanding of the structures, processes and outcomes of primary care practice. We propose to expand the infrastructure of this PBRN to meet 3 aims: 1) To expand RAPP's capacity for research involving health system interventions and minority populations by incorporating primary care practices from an integrated health care system with its own managed care organization. 2) To develop an electronic information infrastructure for the current and expanded network. 3) To establish a "Learning Exchange," that integrates research findings and local knowledge to foster research implementation and practice relevant quality improvement interventions. These aims will be met by enrolled an additional 184 clinicians from 4 primary care specialties in 65 practice sites in a single health care system. This expanded network will be supported by broadening the existing clinician steering committee, communication vehicles and pilot study research mechanisms, and establishing a patient and community advisory board. The network's information infrastructure will be expanded to foster research access to data currently collected by the health system and affiliated managed care organization for quality improvement projects. Additional informatics capacity will be developed through an innovative automated internet- and telephone-based system for gathering patient information. Capacity for dissemination of research information and local learning will be expanded through a new internet-, telephone- and meeting-based learning exchange for sharing of new knowledge. The proposed project will expand the capacity of an established and successful PBRN to generate, disseminate and apply new knowledge that is relevant to the needs of practitioners, health systems and traditionally underserved populations. This expanded infrastructure and new affiliations will foster diversified ongoing network support, and will provide a rich source of experience to contribute to and learn from the efforts of other P20 grant recipients.